用简便方法计算12012201222013221009921981搜(1)2012+20122-20132=2012+(2012+2013)(2012-2013)=2012-4025=-2013(2)100/992+198+1=100/(99+1)2=100/1002=1/1002,121323142434160260586059601/2+(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+……+(1/60+2/60+……+58/60+59/60)=0.5+1+1.5